Magnetotelluric Investigation of the Underlying Structure of Manzaz Volcanic District (Hoggar, Southern Algeria)
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Abstract
The main objective of this study was to model the lithospheric structure of the Manzaz volcanic district (Hoggar) using the magnetotelluric (MT) method. For this purpose, eleven MT stations forming a 70-km long NW-SE profile, intersecting the Manzaz, were modeled. The 2D resistivity model shows an anomalously conductive crust resting on a lithospheric mantle of normal resistivity. The anomalously high conductivity of the middle and lower crust results probably from magma ascent from the asthenosphere to the surface. It could correspond to the presence of partial melting, trapped fluids released by the magma and/or precipitation of mineralization. The conductive structures underlying the Manzaz could correspond to intracrustal magmatic chambers or to magmatic underplating zones at the Moho or at lower/upper crust discontinuities.
Keywords
Manzaz volcanic district Hoggar Magnetotellurics AlgeriaReferences
- 1.Benhallou, A.-Z., Azzouni-Sekkal, A., Bonin, B., Ikhlef-Debabha, F., Ben El Khaznadji, R., Liégeois, J.-P.: Le district volcanic du Manzaz (Hoggar, Sahara algérien): Géologie, pétrologie et mineralogy. Bulletin du Service Géologique de l’Algérie 27, 3–42 (2016)Google Scholar
- 2.Bouzid, A., Bayou, B., Liégeois, J.-P., Bourouis, S., Bougchiche, S.S., Bendekken, A., Abtout, A., Boukhlouf, W., and Ouabadi, A.: Lithospheric structure of the Atakor metacratonic volcanic swell (Hoggar, Tuareg Shield, southern Algeria): Electrical constraints from magnetotelluric data. in Foulger, G.R., Lustrino, M., and King, S.D., eds., The Interdisciplinary Earth: A Volume in Honor of Don L. Anderson: Geological Society of America Special Paper 514 and American Geophysical Union Special Publication 71, p. 239–255 (2015)Google Scholar
- 3.Caldwell, T.G., Bibby, H.M., Brown, C.: The magnetotelluric phase tensor. Geophys. J. Int. 158, 457–469 (2004)CrossRefGoogle Scholar
- 4.Groom, R.W., Bailey, R.C.: Decomposition of magnetotelluric impedance tensor in the presence of local three-dimensional galvanic distortion. J. Geophys. Res. 94, 1913–1925 (1989)CrossRefGoogle Scholar
- 5.Jones, A.G., Chave, A.D., Egbert, G., Auld, D., Bahr, K.: A comparison of techniques for magnetotelluric response function estimation. J. Geophys. Res. 94, 14201–14213 (1989)CrossRefGoogle Scholar
- 6.Kerbadj, N., Bouzid, A., Saibi, H., Bounif, M.O., Bougchiche, S. and Kebede, Y.: 2-D inversion of magnetotelluric data at Dar-Chioukh region (Djelfa, Algeria). The 4th International Conference on Engineering Geophysics, Al-Ain, UAE, 9–12 October 2017, pp 366-369 (2017)Google Scholar
- 7.Mackie, R., Rieven, S., and Rodi, W.,: User’s manual and software documentation for two-dimensional inversion of magnetotelluric data: Earth Resources Laboratory Rpt.: Cambridge, Massachusetts Institute of Technology, 13 p. (1997)Google Scholar
- 8.Siripunvaraporn, W., Egbert, G., Uyeshima, M.: Interpretation of two-dimensional magnetotelluric profile data with three-dimensional inversion: synthetic examples. Geophys. J. Int. 160, 804–814 (2005)CrossRefGoogle Scholar